Propellant lined high velocity accelerator



NOV- 19, 1968 c. A. RODENBERGER 3,411,403

PROPELLANT LINED HIGH VELOCITY ACCELERATOR Filed April 14, 1967 s. mw MM www www N ,A E M e /M 4. W,

3,41 1,403 Patented Nov. 19, 1968 3,411,403 PROPELLANT LINED HIGH VELOCITY ACCELERATOR Charles A. Rodenberger, College Station, Tex. (508 Crescent Drive, Bryan, Tex. 77801) Filed Apr. 14, 1967, Ser. No. 631,045 2 Claims. (Cl. 89-8) ABSTRACT F THE DISCLOSURE A hypervelocity accelerator for a projectile. The projectile is accelerated in a tube lined with an explosive propellant. Ignition of the propellant is caused by passage of the projectile, which continuously generates gas at high pressures in contact with the base of the projectile to drivey it in hypervelocity flight.

This invention relates to a device for accelerating a mass to high velocities.

The invention described herein was made in the performance of work under a NASA contract and is subject to the provisions of Section 305 of the National Aeronautics and Space Act of 1958, Public Law 85-568 (72 Stat. 435; 42 U.S.C. 2457).

With the advent of space exploration, the physics and dynamics of hypervelocity flight, as well as impact reactions, must be studied under simulated conditions. One mode of study devised for this purpose is to propel a projectile or mass in a barrel or launch tube to great speeds.

Current devices propel the projectile or mass by driving it with a high pressure gas forced into the barrel. As the projectile velocity exceeds the speed of sound in the driver gas, the pressure on it begins to reduce rapidly and consequently the acceleration of the projectile is reduced, limiting its maximum attainable velocity.

Accordingly, it is an object of this invention to propel a projectile or mass in a barrel to greater velocities than has been attainable heretofore.

Another object of this invention is to provide an acceleration tube or barrel lined with a chemically explosive propellant adapted to be ignited by passage of the projectile itself, for continuously generating at a high rate, a gas behind the projectile for uniformly and continuously accelerating it.

A still further object of this invention is to provide a propellant lined mass accelerator of the character indicated, the resultant velocity of the mass being limited only by the tube length and the pressure capability of the propellant.

Further objects and advantages of the invention will become apparent from the following description and claims, and from the accompanying drawings, wherein:

FIGURE 1 is a side view in elevation of the hypervelocity accelerator of the present invention, including portions illustrated schematically;

FIGURE 2 is an enlarged cross-sectional view taken substantially along the plane indicated by line 2--2 of FIGURE 1; and

FIGURE 3 is an enlarged, fragmentary cross-sectional view taken substantially along the plane indicated by line 3 3 of FIGURE 1.

Referring now to the drawing, -wherein like numerals indicate like elements throughout the several views, the

propellant lined high velocity accelerator of the present invention is generally indicated by the numeral 10.

The accelerator 10 includes a launch tube or barrel 12 and a standard ignition device 14.

The ignition device 14 could be an ordinance type device to initiate a high temperature and pressure of a gas, and consequent motion of a projectile or mass 16 in barrel 12, or alternatively, it could be a complete rst stage acceleration assembly to have accelerated the projectile 16 to a predetermined velocity before entering the barrel. In the latter instance the accelerator would act as a velocity augmentation device.

The ignition device 14 is of standard construction and forms no part of the instant invention. For examples of suitable ignition devices, see U.S. Patents Nos. 3,126,789 and 3,148,587.

In order to increase the velocity of the projectile 16 as it moves through barrel 12, the barrel is lined with a chemically explosive propellant 18. The propellant to be used can be made from any material rated as a low or secondary chemical explosive or a high chemical explosive that can be formed into a plastic adhesive mass, and which is capable of generating gas at a high rate. For example, nitrocellulose dissolved in a suitable solvent can be applied as a liner by conventional methods used to internally coat tubular articles.

As the projectile 16 is propelled down barrel 12, it causes the propellant 18 to explode behind it, continuously building up a high pressure gas zone or pocket 20 on its base 22, resulting in its continuous and substantially uniform acceleration.

Ignition of the propellant 18 is due to three sources: (1) the friction generated by projectile 16; (2) the pressure of the projectile against the propellant; and (3) the high temperature and pressure of the gas behind the projectile.

As the result of using a chemically explosive propellant, responsive to heat and pressure, lining barrel 12, there is no chance of the projectile outrunning the generated gas to cause a reduction in pressure on its base 22, and hence a reduction in acceleration. A constant gas pocket is maintained impinged against base 22 of projectile 16, providing a constant energy source for driving the projectile. In order to accomplish this, the propellant lining must be ignited and must react in micro-seconds, and accordingly, the propellant must be chemically explosive in response to passage of the projectile,

FIGURE 3 illustrates the resultant movement of projectile 16 in barrel 12. The projectile moves to the right because the ignited propellant has expanded on its left side causing high pressure gas to impinge on its base and the resulting unbalanced force causes a continuous and substantially constant acceleration. This acceleration will cause the projectile to reach a maximum velocity limited only by the tube or Ibarrel length and the pressure capability of the propellant.

The barrel 12 may be made from a recoverable material of high structural strength to resist internal pressure, or it may be made expendable.

The accelerator itself also has ordinance capabilities. A weapon with a propellant lined barrel as disclosed, will be capable of shooting projectiles with increased range.

While a specific embodiment of my invention has been disclosed in the foregoing description, it will be understood that various modifications within the spirit of the invention may occur to those skilled in the art. Therefore, it is intended that no limitations be placed on the invention except as defined by the scope of the appended claims.

I claim:

1. Acceleration apparatus comprising a mass, an elon- 5 2. Apparatus in accordance with claim 1 wherein said propellant lining is concentric with said tubular member.

References Cited UNITED STATES PATENTS 2,971,473 2/1961 Raynaud 89-8 X 3,031,933 5/1962 Kern et al 89-8 3,253,511 5/1966 Zwicky 89-1.818 X FOREIGN PATENTS 407,860 5/ 1944 Italy.

SAMUEL W. ENGLE, Primary Examiner. 

